Twin strand continuous casting apparatus with a tundish load balancing vessel

ABSTRACT

A twin strand continuous metal casting apparatus is disclosed including two casting molds, a vertical arbor assembly, and a tundish carrier assembly mounted on the arbor with a pair of forks each carrying a tundish projecting radially outward from a common hub around the arbor. A tundish loading vessel is provided having a pair of discharge spouts projecting in opposite directions. A support is connected between the forks, which carry the tundish loading vessel transversely above the forks with each spout over one of the tundishes. A rocking mechanism is provided to rock the loading vessel for varying the rate of metal discharge through the two spouts to the two tundishes and equalize the load of molten metal in the two tundishes. The rocking assembly comprises linkages which automatically respond to unequal loading of the two tundishes and tilt the loading vessel to increase the flow of metal to the lesser loaded of the two tundishes.

United States Patent [191 Schoffmann [4 1 Feb. 18, 1975 TWIN STRANDCONTINUOUS CASTING APPARATUS WITH A TUNDISI-I LOAD BALANCING VESSEL [75]Inventor: Rudolf Schoffmann, Linz, Austria [73] Assignee: Allis-ChalmersCorporation,

Milwaukee, Wis.

[22] Filed: Jan. 2, 1974 [2]] Appl. No.: 430,032

[52] US. Cl. 164/281, 164/337 [51] Int. Cl B22d 11/10, B22d 37/00 [58]Field of Search 164/281, 335, 337;

[56] References Cited UNITED STATES PATENTS 3,552,902 1/1971 Schoffmannet al 164/281 3,773,228 11/1973 Koch et al. 164/281 X FOREIGN PATENTS ORAPPLICATIONS 701,189 12/1953 Great Britain 164/281 Primary ExaminerRobert D. Baldwin Attorney, Agent, or FirmArthur M. Streich ABSTRACT Atwin strand continuous metal casting apparatus is disclosed includingtwo casting molds, a vertical arbor assembly, and a tundish carrierassembly mounted on the arbor with a pair of forks each carrying atundish projecting radially outward from a common hub around the arbor.A tundish loading vessel is provided having a pair of discharge spoutsprojecting in opposite directions. A support is connected between theforks, which carry the tundish loading vessel trans versely above theforks with each spout over one of the tundishes. A rocking mechanism isprovided to rock the loading vessel for varying the rate of metaldischarge through the two spouts to the two tundishes and equalize theload of molten metal in the two tundishes. The rocking assemblycomprises linkages which automatically respond to unequal loading of thetwo tundishes and tilt the loading vessel to increase the flow of metalto the lesser loaded of the two tundishes.

8 Claims, 5 Drawing Figures PATENTED FEB] 1 75 SHEET 10F 3 FM'ENTEU FEB1 8 5 SHEET 2 OF 3 1 TWllN STRAND CONTINUOUS CASTING APPARATUS WITH-ll ATUNDISH LOAD BALANCING VESSEL CROSS REFERENCE TO RELATED PATENT IAPPLICATION This application discloses an invention which may be appliedand is herein disclosed as being applied, to a continuous castingapparatus which is the subject of my copending U.S. Pat. applicationentitled Continuous Casting Apparatus with Movable Ladles andTundishes," Ser. No. 430,l95, filed concurrently with this application.

BACKGROUND or THE INVENTION 1. Field of the Invention This inventionrelates to a coontinuous casting of metals and in particular to a twinstrand continuous casting apparatus with movable ladles and tundishes,and balanced metal flow to two casting molds. This invention furtherrelates to improvements to apparatus such as disclosed in a prior patentto Anton Kubera and me, U.S. Pat. No. 3,552,902 ofJan. 5, 1971 and myaforesaid copending patent application.

2. Description of the Prior Art Twin strand continuous casting machinesare known to those skilled in this technology. U.S. Pat. No. 2,804,665discloses a twin strand caster having a single tundish with two orificesfor discharging metal simultaneously or alternately to two castingmolds. This tundish is rocked to provide unbalanced metal flow into themolds according to a predetermined cycle.

Prior art patents also disclose arrangements for supporting the greatweight of ladles and tundishes, with apparatus including carriageshaving wheels or rollers engaging railway tracks to support the ladlesand/or tundishes being moved into and away from casting positions.Examples of such arrangements are disclosed in U.S. Pat. No. 3,344,847,Oct. 3, 1967; U.S. Pat. No. 3,382,913, May 14, 1968; U.S. Pat. No.3,446,269, May 27, 1969; and U.S. Pat. No. 3,456,713, July 22, 1969.

U.S. Pat. No. 3,552,902, Jan. 5, 1971, granted to Anton Kubera and me,discloses a pair of ladle carrier arms pivotally mounted on a commonvertical arbor, and a pair of tundishes each separately pivotable aboutits own vertical support column, with each of the ladles and tundishesbeing movable into and away from casting positions.

U.S. Pat. No. 3,556,349 discloses a pair of tundishes mounted to pivottogether on a single vertical arbor and which can be raised and lowered,but which will require separate support structure for one or moreladles.

My copending patent application, to which cross reference has been made,discloses ladles and tundishes mounted on a common central arborassembly which requires no other support for moving the ladles andtundishes into and away from casting positions.

SUMMARY OF THE PRESENT INVENTION It is a feature of the presentinvention that a tundish carrier assembly is provided with a pair oftundishes carried by forks projecting radially outward from a common hubaround an arbor, with a support connected between the forks whichcarries a tundish loading vessel transversely above the two tundishesfor loading both tundishes with molten metal through a LII pair ofdischarge spouts, one over each tundish. The carrier assembly ispivotally mounted on the arbor to move both tundishes and their loadingvessel in a horizontal plane as a single unit over two casting molds forcasting twin strands of metal.

Another feature of the present invention is that the tundish loadingvessel is mounted to rock on its support for varying the rate ofdishcarge to the two tundishes, and with an axis of support moving asthe loading vessel is tilted, to be beneath the center of gravity of theload of molten metal within the loading vessel.

Another feature of the invention is that a mechanism is provided whichautomatically responds to unequal loading of the two tundishes bytilting the loading vessel toward the lesser loaded of the twotundishes.

The objects of the invention comprise providing for the aforesaidfeatures and with a compact single arbor assembly, support for movingthe ladles, tundishes and tundish loading vessel into and away fromcasting position.

Other features and objects of the invention that have been attained willappear from the more detailed description to follow with reference to anembodiment of the invention shown in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 of the accompanying drawingsshow a side elevation, partly in section, a ladle and tundish supportapparatus according to the present invention;

FIG. 2 is a top view of the apparatus shown in FIG. 1;

FIG. 3 is a view taken along line III-III in FIG. 1 and viewing thestructure in the direction indicated by arrows;

FIG. 4 is a view in section taken along line IVIV in FIG. 2 and viewingthe structure in the direction indicated by arrows; and

FIG. 5 is a fragmentary view in section taken along line VV in FIG. 2and viewing the structure in the direction indicated by arrows.

DESCRIPTION OF THE [PREFERRED EMBODIMENT Referring to FIG. l and FIG. 2of the drawing, an apparatus is shown for continuous casting of metal ina pair of casting molds 1 and la opening at or above a casting floor 2shown in FIG. 1. The apparatus is provided with a central vertical arborassembly 3 having an upper cylindrical column 4 telescopically arrangedwithin a lower cylindrical column member 5 with column 4 projectingvertically upward from column 5. The column member 5 is secured, as bywelding, to support structures 6 beneath the casting floor 2. column 5has a circular bottom piece 7 also welded to support structure 6, andhaving a square central opening through which a square key 8 projects(see also FIG. 3) to provide alignment of the arbor assembly 3 relativeto the support structure 6.

Column 4 is telescopically fitted within the upper and open end ofcolumn 5. One or more keys 10 are provided which are arranged invertical parallel alignment with arbor 3, which are welded to the innersurface of column 5 and project into a vertical slot 111 defined in theouter surface of column 4, to lock column 4 against rotation whilepermitting vertical. movement of column 4 within column 5.

A pair of ladle carrier arms 14, are mounted on an upper portion ofcolumn 4 to carry a pair of ladles 16, 17. The arms 14, 15 rest uponthrust bearing collars 18, 19, respectively, that are secured to column4. Antifriction roller bearings 22 are interposed between arm 14 andcolumn 4, and antifriction roller bearings 23 are interposed between arm15 and column 4, and thus both arms 14, 15 are pivotable around column4, each in a horizontal plane. The manner in which such pivotablemovement is provided for will now be described. A nonrotating ring gear25 is rigidly secured, as by welding, to the column 4 between arms 14,15. A reversible electric motor 26 is mounted on arm 14 with its driveshaft 27 projecting downwardly. A pinion gear 28 is mounted on driveshaft 27 and engages ring gear 25. When motor 26 turns shaft 27 andpinion gear 28, motor 26 and arm 14 pivot horizontally around column 4because, as has been stated, ring gear 25 cannot turn as it is welded tocolumn 4 and column 4 is held against rotation by the keys 10. Likewise,a reversible electric motor 29 is mounted on arm 15 but with its driveshaft projecting upwardly. A pinion gear 31 is mounted on drive shaftand also engages ring gear 25. When motor 29 turns its shaft 30 andpinion gear 31, motor 29 and arm 15 pivot horizontally around column 4.Electric power for motors 26 and 29 may be delivered to movable arms 14,15 for the motors by such as brushes (not shown) engaging slip rings 32on gear 25. Column 4, arms 14 and 15, ladles 16, 17, ring gear 25, andmotors 26 and 29, are also shown in the top view of FIG. 2.

Referring again to FIG. 1, in addition to arms 14, 15, and ladles 16, 17being pivotable about the arbor assem bly 3, such arms anad ladles mayalso be raised and lowered. As shown in FIG. 1 the arms 14, 15 are intheir lowest position, with the thrust bearing collar 19 resting upon anannular cap 35 fastened to the top of the lower column 5. Column 4, arms14, 15 and ladles l6, 17 may be raised from the position shown in FIG.1, and then lowered again, by a reversible lift mechanism 37 arrangedwithin the lower column 5 and beneath the upper column 4. As shown inFIG. 3, the lift mechanism 37 may comprise several units (six are shown)each preferably comprising a cylinder defining block 38 containing apiston 39 actuated by hydraulic fluid pressure.

With reference again to FIG. 1, a pair of tundish carrier arms 40, 41are mounted on an upper portion of the lower column 5. As shown in FIG.2, arm carries a pair of tundishes 42, 42a and arm 41 carries a pair oftundishes 43, 43a. As shown in FIG. 1, the arms 40, 41 rest upon thrustbearing collars 44, 45, respectively, that are secured to column 5.Antifriction roller bearings 48 are interposed between arm 40 and column5, and antifriction roller bearings 49 are interposed between arm 41 andcolumn 5, and thus both arms 40, 41 are pivotable around column 5, eachin a horizontal plane. The manner in which the pivotable movement ofarms 40, 41 is provided for is similar to that which has been describedfor the arms l4, 15. That is, a nonrotating ring gear 51 is rigidlysecured, as by welding, to the column 5 between arms 40, 41. areversible electric motor 52 is mounted on arm 40 on the opposite sideof column 5 from tundish 42. Motor 52 is arranged with its drive shaft53 projecting downwardly. A pinion gear 54 is mounted on drive shaft 53and engages ring gear 51. When motor 52 turns shaft 53 and pinion gear54,

motor 52 and arm 40 pivot horizontally around column 5 because, as hasbeen stated, ring gear 51 cannot turn as it is welded to column 5 andcolumn 5 is held against rotation because it is welded to supportstructure 6. Likewise, a reversible electric motor 55 is mounted on arm41 (on the opposite side of column 5 from tundish 43) but with its driveshaft 56 projecting upwardly. A pinion gear 57 is mounted on drive shaft56 and also engages ring gear 51. when motor 55 turns its shaft 56 andpinion gear 57, motor 55 and arm 41 pivot horizontally around column 5.Electric power for motors 52 and 55 may also be delivered to movablearms 40, 41 for the motors by such as brushes (not shown) engaging sliprings 58 on gear 51.

In addition to arms 40, 41 and tundishes 41, 42a, 43, 43a beingpivotable about the arbor 3, the tundishes may also be raised andlowered. The means for accomplishing this is identical for both tundisharms and therefore only tundish arm 40 will be described. Tundishcarrier arm 40 comprises a hub assembly 60 mounted around the lowercolumn 5 and as shown in FIG. 2 a pair tundish supporting forks 61, 61aproject radially outward from hub assembly 60. The forks 61, 61a areconnected together by a cross beam 61b and to the hub 60 for verticalmovement relative to the hub 60. The hub 60 defines a pair of slots 62,63. Only slot 62 can be seen in FIG. 1 but both slots 62, 63 are visiblein the top view of FIG. 2. The fork cross beam 61b, as shown in FIG. 2,is provided with vertical guide bars 64 and 65 which project into slots62, 63 to guide movement of beam 61b and forks 61, 61a up and downrelative to hub 60. The movement of beam 61b and forks 61, 61a isprovided for by winch means 67 shown in FIG. 1 as comprising a hydraulicfluid pressure operated cylinder 68 connected to hub 60 which operatesto move a piston rod 69 up and down. A roller 70 is connected to theupper end of rod 69. A cable 71 is secured to hub 60, looped aroundroller 70 and a second roller 72, and cable 71 extends downwardly and issecured to forks 61, 61a. Fork 61 is shown in FIG. 1 to be in itsuppermost position. To lower forks 61, 61a, rod 69 and roller 70 aremoved upwardly and cable 71 moves over the second roller 72 clockwise,as shown, as gravity moves forks 61, 61a downwardly. To raise forks 61,61a again, rod 69 and roller 70 are moved downwardly to pull cable 71counterclockwise over the second roller 72 and forks 61, 61a are pulledupwardly. Thus forks 61, 61a and tundishes 42, 42a can be raised andlowered relative to the arbor assembly 3 and relative to ladles 16, 17.

A tundish loading vessel 75 is shown in FIG. 1 as being arranged overtundish 42 and beneath ladle 16. The vessel 75 will be described furtherwith reference to FIG. 2 and FIG. 4. The vessel 75 has a pair ofdischarge spouts 76, 77 projecting from opposite sides of the vessel 75and as shown in FIG. 4, vessel 75 may also be provided with a cover 78having a single entrance port 79.

Support means 80 will'now be described with reference to- FIG. 4, whichcarry vessel 75 transversely above the forks 61, 61a with spout 76 overtundish 42 and spout 77 over tundish 42a. The support means 80 comprisea cross beam 81 connected between forks 61, 61a, vertical posts 82, 83mounted on beam 81, and a table 84 connected to posts 82, 83 in aposition above beam 81. Means to accommodate rocking or tilting supportof vessel 75 are interposed between the vessel 75 and table 84, whichcomprise an arcuate gear segment 85 secured, as by welding, to thebottom of vessel 75, and a planar gear rack 86 mounted on the table 84.The tops of posts 82, 83 project upwardly from table 84 toward notches87, 88 formed in gear segment 85, to provide for limiting the anglethrough which vessel 75 can tilt in either direction.

Means to rock or tilt the tundish loading vessel 75 on the support means80 comprise a pair of balance assemblies 90, 91. Since the balanceassemblies 90, 91 are identical, only assembly 90 shall be described indetail. The balance assembly 90 comprises (see FIG. 5) a first linkage92 and a second linkage 93.

With reference to FIG. 5, the first linkage 92 comprises a fluidpressure operated axially expandable motor 95 connected on one end by apivot 96 to fork 61, for pivotal movement in a vertical plane, and has apiston rod 97 projecting from motor 95 which is pivotally connected to across arm 98 intermediate the ends of cross arm 98. A lower end 99 ofarm 98 is pivotally connected to a frame 100 that rests on an end piece101 of the second linkage 93. An upper end 102 of arm 98 engages a hook103 attached to the radially inner end of tundish 42. Arm 98 makescontact with tundish 42 as shown in phantom lines. Piston rod 97 is thenmoved toward pivot 96 and the upper end 102 of cross arm 98 engages hook103 and lifts the radially inner end of tundish 42 off fork 61 and theweight of tundish 42 (and its load of molten metal) then causes frame100 to bear downwardly on end piece 101 of the second linkage 93, with aforce depending upon the load within tundish 42. The piece 101 ismounted on an arm 105 of the second linkage 93. The arm 105 is connectedby a pivot 106 to a member 107 which is in turn rigidly attached to fork61. Referring now to FIG. 4 the end of arm 105 remote from piece 101carries a roller 109 which engages a push rod 110. Push rod 110 isaxially and vertically slidable in a sleeve 111 attached to cross beam81. Push rod 110 projects upwardly from cross beam 81 and table 84 toengage the bottom of tundish loading vessel 75. Sleeve 110 is mounted onbeam 81 at a location between a first vertical plane XX projectingradially from arbor 3 through the centerline of vessel 75, and a secondplane Y-( projecting radially from arbor 3 through spout 76.

In the operation of the balance system, the downward force on piece 101resulting from the weight of tundish 42 and the load of metal therein,is transmitted as an upward force to the bottom of tundish loadingvessel 75. Since balance assemblies 90 and 91 are identical, except thatassembly 91 is on the opposite side of plane X-X from assembly 90, whentundishes 42, 42a are equally loaded with molten metal the assemblies 90and 91 transmit equal and balanced forces and vessel 75 remainshorizontal and discharging metal equally to both tundishes 42, 42a.However if, for example, tundish 42 carries a greater load of metal thantundish 42a, the balance assembly will transmit a greater force throughpush rod 110 to vessel 75 than is transmitted to vessel 75 by balanceassembly 91, and vessel 75 will then tilt toward tundish 42a, as shownwith phantom lines in FIG. 4, until the accelerated flow to tundish 42adue to tilting vessel 75, restores equal loading in the two tundishes42, 42a.

1n the operation of the entire apparatus, with reference to FIG. 2, apair of tundishes, for example tundishes 42, 42a, are positioned overthe molds 1, 1a.

Ladle carrier arm 14, with ladle 16 filled with molten metal, may thenbe pivoted counterclockwise around column 4 until ladle 16 is overtundish loading vessel 75. The vertical position of ladle 16 may beadjusted by the lift mechanism 37 and the vertical position of tundishes42, 42a and vessel may be adjusted as desired by the winch means 67. Thepouring may then begin. When ladle 16 is almost empty, ladle l7 filledwith molten metal will be pivoted clockwise around column 4 to aposition alongside ladle 16. When ladle 16 is empty, ladle 16 will bepivoted clockwise away from vessel 75 and ladle 17 is pivoted clockwiseto a position over tundish loading vessel 75. Tundish loading vessel 75and tundishes 42, 42a have sufficient capacity that they do not emptyduring the brief time required to move ladle 16 out of the way and ladle17 into position over the tundish loading vessel 75. The empty ladle 16will be pivoted clockwise to a refill position on the opposite side ofarbor 3 from molds 1, 1a. When ladle 16 is refilled it will be pivotedcounterclockwise to a position alongside ladle 17 and when ladle 17 isempty it will be moved counterclockwise to the refill position and ladle16 will be moved counterclockwise over tundish loading vessel 75. Whenthe tundish loading vessel 75 and tundishes 42, 42a are to be taken outof operation, casting is interrupted briefly as arm 40 is turnedclockwise around the arbor assembly 3 to make room for arm 41 to turnclockwise and locate tundish loading vessel 75a and tundishes 43, 43aover molds 1, 1a. Arm 40 continues to turn clockwise until arriving at asuitable position for lowering forks 61, 61a to lower tundishes 42, 42aon suitable carriage means (not shown). New or refurbished tundishes maythen be moved over forks 61, 61a and forks 61, 61a raised to lift andcarry the new or refurbished tundishes, when needed, over molds 1 and1a. Additionally, the vertical adjustability of forks 61, 6111 as wellas hub 60 and the ladle arms 14, 15 can be utilized to provide improvedaccess to various parts of the apparatus to facilitate inspection andmaintenance work.

With a pair of tundishes such as 42, 42a and a tundish loading vesselsuch as 75, in position over molds 1, 1a, molten metal is poured from aladle 16 or 17, through port 79 into vessel 75. The tundish loadingvessel 75 discharges molten metal through both spouts 76, '77 to thetundishes 42, 42a. The tundish loading vessel 75 with its arcuate gearsegment may be rocked or tilted on the planar gear rack 86 and the loadapplied to gear rack 86 moves as vessel 75 and the arcuate gear rocksthereon, to a location that is always beneath the center of gravity ofthe charge of molten metal within vessel 75, and thus the metal chargeitself produces no unbalanced forces on the support means 80.Furthermore, the rocking or tilting of the tundish loading vessel 75when the tundishes 42, 42a are unequally loaded, occurs automatically asthe balance assemblies 90, 91 operate to tilt the vessel as required torestore balanced loading of the tundishes.

The foregoing is accomplished with an apparatus that utilizes only asingle vertical arbor assembly to support and move ladles, tundishloading vessels and tundishes as required for such operations andpurposes as have been described, and thus it has been shown how thefeatures and objects of the present invention have been attained in apreferred manner. However, modification and equivalents of the disclosedconcepts such as readily occur to those skilled in the art are intendedto be included in the scope of this invention. Thus, the scope of theinvention is intended to be limited only by the scope of the claims suchas are or may hereafter be, appended hereto.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

l. A twin strand continuous metal casting apparatus comprising:

a. two casting molds spaced apart in a common horizontal plane;

b. a vertical arbor assembly horizontally spaced from both molds;

c. a tundish carrier assembly mounted on the arbor for pivotal movementin a horizontal plane above the molds, said assembly having a hub aroundthe arbor and a pair of forks projecting radially outward from the hubin a common horizontal plane;

d. a plurality of tundishes, with one tundish mounted on each fork;

e. a tiltable tundish loading vessel having a pair of discharge spoutsprojecting from opposite sides of the vessel;

f. vessel supporting means connected between said forks and carrying thetundish loading vessel transversely above the forks with each of thespouts over one of the tundishes; and

g. ladle supporting means adapted to carry a ladle containing moltenmetal and operative to move a ladle of molten metal into a teemingposition over the tundish loading vessel to discharge metal thereto forselective flow through both said spouts to both said tundishes.

2. An apparatus according to claim 1 having an arcuate gear segmentmounted on the bottom of the tundish loading vessel above the vesselsupporting means and having gear teeth projecting downwardly therefrom,a

planar gear rack mounted on the vessel supporting means having gearteeth engaging the teeth of the arcuate gear segment, and rocking meansconnected to the tundish loading vessel constructed and arranged to tiltthe tundish loading vessel and arcuate gear on the supporting means andplanar rack gear for varying the rate of metal discharge from theloading vessel through said spouts to said tundishes.

3. An apparatus according to claim 2 with said rocking means having apair of balance assemblies each comprising:

a. a first linkage connected on one end to a radially inner portion ofsaid fork and with a second end thereof being adapted to engage aradially inner end of the tundish on said fork for lifting the radiallyinner end of the tundish upwardly from its supporting fork;

b. a second linkage carried by said fork and having a first end engagingthe second end of the first linkage, and a second end engaging thebottom of the tundish loading vessel at a location between a firstvertical plane projecting radially from the arbor through the center ofthe vessel and a second vertical plane projecting radially from thearbor through the vessel spout above the tundish engaged by the firstlinkage, with said second linkage being operative to transmit downwardforce applied thereto by the first linkage as an upward lifting force tothe bottom of the tundish loading vessel; whereupon the pair of balanceassemblies respond to unequal loading of the two tundishes and tilt thetundish loading vessel toward the lesser loaded tundish to increase theflow of molten metal from the loading vessel to the lesser loaded of thetwo tundishes and decrease the flow of molten metal from the loadingvessel to the greater loaded of the two tundishes until a balancedloading of the two tundishes is restored.

4. An apparatus according to claim 3 in which the first linkagecomprises:

a. a fluid pressure axially expandable motor connected on a first end tosaid fork for pivotal movement in a vertical plane b. a cross arm in avertical plane connected intermediate the ends thereof to a second endof the expandable motor, said cross arm having a lower end connected toa pivot carried by the first end of the second linkage, and said crossarm having an upper end engageable with said tundish for lifting theradially inner end of the tundish off the fork when said motor pivotsthe cross arm about the pivot at the lower end of said cross arm, tothus apply the downward force of tundish loading to the first end of thesecond linkage.

5. An apparatus according to claim 1 in which said i ladle supportingmeans comprise first and second carrier arms mounted in verticallyspaced arrangement on an upper portion of the arbor assembly above thetundish carrier assembly for independent pivotal movement of said armsrelative to said arbor and each other in a horizontal plane.

6. An apparatus according to claim 5 in which the tundish carrierassembly comprises third and fourth carrier arms mounted in verticallyspaced arrangement on the arbor assembly for independent pivotalmovement of the third and fourth arms relative to the arbor assembly ina horizontal plane, and with each of the tundish carrier arms having apair of forks for carrying tundishes and a said tundish loading vesselabove each pair of tundishes.

7. An apparatus according to claim 5 in which:

a. the vertical arbor assembly comprises telescoping upper and lowercolumn members with the lower column adapted to be rigidly attached tosupport structure and the upper column projecting upwardly from andmovable relative to the lower column;

b. the first and second ladle carrier arms are mounted in verticallyspaced arrangement on the upper column for independent pivotal movementof said arms relative to said upper column in a horizontal plane;

0. a vertically arranged key attached to one of said column members andprojecting into an elongated vertical slot defined in the other of saidcolumn members to limit movement of the upper column to verticalmovement; and

d. a reversible lift mechanism between the telescoping column membersfor lifting and lowering the upper column and both of the ladle carrierarms relative to the tundish loading vessel.

8. An apparatus according to claim 6 in which the third and fourth armsare each constructed with the pair of forks connected to the hubsthereof by a winch mounted on the hub having a cable connected to theforks for raising and lowering the pair of forks, the tundish loadingvessel supporting means, and the tundish loading vessel relative to theladle carrier arms and the two casting molds.

1. A twin strand continuous metal casting apparatus comprising: a. twocasting molds spaced apart in a common horizontal plane; b. a verticalarbor assembly horizontally spaced from both molds; c. a tundish carrierassembly mounted on the arbor for pivotal movement in a horizontal planeabove the molds, said assembly having a hub around the arbor and a pairof forks projecting radially outward from the hub in a common horizontalplane; d. a plurality of tundishes, with one tundish mounted on eachfork; e. a tiltable tundish loading vessel having a pair of dischargespouts projecting from opposite sides of the vessel; f. vesselsupporting means connected between said forks and carrying the tundishloading vessel transversely above the forks with each of the spouts overone of the tundishes; and g. ladle supporting means adapted to carry aladle containing molten metal and operative to move a ladle of moltenmetal into a teeming position over the tundish loading vessel todischarge metal thereto for selective flow through both said spouts toboth said tundishes.
 2. An apparatus according to claim 1 having anarcuate gear segment mounted on the bottom of the tundish loading vesselabove the vessel supporting means and having gear teeth projectingdownwardly therefrom, a planar gear rack mounted on the vesselsupporting means having gear teeth engaging the teeth of the arcuategear segment, and rocking means connected to the tundish loading vesselconstructed and arRanged to tilt the tundish loading vessel and arcuategear on the supporting means and planar rack gear for varying the rateof metal discharge from the loading vessel through said spouts to saidtundishes.
 3. An apparatus according to claim 2 with said rocking meanshaving a pair of balance assemblies each comprising: a. a first linkageconnected on one end to a radially inner portion of said fork and with asecond end thereof being adapted to engage a radially inner end of thetundish on said fork for lifting the radially inner end of the tundishupwardly from its supporting fork; b. a second linkage carried by saidfork and having a first end engaging the second end of the firstlinkage, and a second end engaging the bottom of the tundish loadingvessel at a location between a first vertical plane projecting radiallyfrom the arbor through the center of the vessel and a second verticalplane projecting radially from the arbor through the vessel spout abovethe tundish engaged by the first linkage, with said second linkage beingoperative to transmit downward force applied thereto by the firstlinkage as an upward lifting force to the bottom of the tundish loadingvessel; whereupon the pair of balance assemblies respond to unequalloading of the two tundishes and tilt the tundish loading vessel towardthe lesser loaded tundish to increase the flow of molten metal from theloading vessel to the lesser loaded of the two tundishes and decreasethe flow of molten metal from the loading vessel to the greater loadedof the two tundishes until a balanced loading of the two tundishes isrestored.
 4. An apparatus according to claim 3 in which the firstlinkage comprises: a. a fluid pressure axially expandable motorconnected on a first end to said fork for pivotal movement in a verticalplane b. a cross arm in a vertical plane connected intermediate the endsthereof to a second end of the expandable motor, said cross arm having alower end connected to a pivot carried by the first end of the secondlinkage, and said cross arm having an upper end engageable with saidtundish for lifting the radially inner end of the tundish off the forkwhen said motor pivots the cross arm about the pivot at the lower end ofsaid cross arm, to thus apply the downward force of tundish loading tothe first end of the second linkage.
 5. An apparatus according to claim1 in which said ladle supporting means comprise first and second carrierarms mounted in vertically spaced arrangement on an upper portion of thearbor assembly above the tundish carrier assembly for independentpivotal movement of said arms relative to said arbor and each other in ahorizontal plane.
 6. An apparatus according to claim 5 in which thetundish carrier assembly comprises third and fourth carrier arms mountedin vertically spaced arrangement on the arbor assembly for independentpivotal movement of the third and fourth arms relative to the arborassembly in a horizontal plane, and with each of the tundish carrierarms having a pair of forks for carrying tundishes and a said tundishloading vessel above each pair of tundishes.
 7. An apparatus accordingto claim 5 in which: a. the vertical arbor assembly comprisestelescoping upper and lower column members with the lower column adaptedto be rigidly attached to support structure and the upper columnprojecting upwardly from and movable relative to the lower column; b.the first and second ladle carrier arms are mounted in vertically spacedarrangement on the upper column for independent pivotal movement of saidarms relative to said upper column in a horizontal plane; c. avertically arranged key attached to one of said column members andprojecting into an elongated vertical slot defined in the other of saidcolumn members to limit movement of the upper column to verticalmovement; and d. a reversible lift mechanism between the telescopingcolumn members for lifting and lowering the upper column and both of theladle carrier arms relative to the tundish loading vessel.
 8. Anapparatus according to claim 6 in which the third and fourth arms areeach constructed with the pair of forks connected to the hubs thereof bya winch mounted on the hub having a cable connected to the forks forraising and lowering the pair of forks, the tundish loading vesselsupporting means, and the tundish loading vessel relative to the ladlecarrier arms and the two casting molds.